Interpretive Summary: Hybrid striped bass, a hybrid fish made from striped bass and white bass, from 44 different families were raised indoors in tanks for 42 days after they hatched. Body length and weight was measured in fish from each family to determine how much the choice of male or female parent affected how much each family grew. Statistical analysis showed that growth of these fish was affected by which male or female was used to make them, but which female was used made the biggest difference. Results demonstrate that you should be able to make bigger hybrid striped bass by selectively breeding the best parents for future use.

Technical Abstract:
Heritability of body length and body weight was evaluated in 44 families of hybrid striped bass raised in replicated indoor tanks to 42 days post hatch. Fingerlings averaged 36.7 (' 2.6 SD) (range 27.7-45.3) mm and 0.53 (' 0.10) (0.22-1.22) g across all families after 42 days of indoor rearing. Analysis of variance demonstrated highly significant differences in length and weight of fingerlings among different paternal and maternal half-sib families (P < 0.0001). There were significant sire and dam components of phenotypic variance for both traits, with the dam component of variance higher than the sire component. Corresponding estimates of heritability were between 0.67 and 1.11 for dams and 0.44 and 0.48 for sires. These results indicate that a substantial portion of the selection differential would be expected to be gained in the offspring of the selected pure-line parents in an interspecific selective improvement program. By determining genetic parameters at multiple life stages, appropriate selection criteria can be developed at the earliest possible time during the production cycle.